scholarly journals Characterization of the evolutionary dynamics of influenza A H3N2 hemagglutinin

2020 ◽  
Author(s):  
Maggie Haitian Wang ◽  
Jingzhi Lou ◽  
Lirong Cao ◽  
Shi Zhao ◽  
Paul KS Chan ◽  
...  
Keyword(s):  
North America ◽  
Influenza A ◽  
Evolutionary Dynamics ◽  
Herd Immunity ◽  
Genomic Region ◽  
Point Of View ◽  
Population Immunity ◽  
Epidemiology Data ◽  
Mutation Dynamics

AbstractVirus evolution drives the annual influenza epidemics in human population worldwide. However, it has been challenging to evaluate the mutation effect of the influenza virus on evading the population immunity. In this study, we introduce a novel statistical and computational approach to measure the dynamic molecular determinants underlying epidemics by the effective mutations (EMs), and account for the time of waning mutation advantage against herd immunity by the effective mutation periods (EMPs). Extensive analysis is performed on the genome and epidemiology data of 13-year worldwide H3N2 epidemics involving nine regions in four continents. We showed that the identified EM processed similar profile in geographically adjacent regions, while only 40% are common to Europe, North America, Asia and Oceania, indicating that the regional specific mutations also contributed significantly to the global H3N2 epidemics. The mutation dynamics calibrated that around 90% of the common EMs underlying global epidemics were originated from South East Asia, led by Thailand and India, and the rest were originated from North America. New Zealand was found to be the dominate sink region of H3N2 circulation, followed by UK. All regions might act as the intersection in the H3N2 transmission network. The proposed methodology provided a way to characterize key amino acids from the genetic epidemiology point of view. This approach is not restricted by the genomic region or type of the virus, and will find broad applications in identifying therapeutic targets for combating infectious diseases.

scholarly journals Transmission of Eurasian avian H2 influenza virus to shorebirds in North America

1999 ◽  
Vol 80 (12) ◽  
pp. 3167-3171 ◽  
Author(s):  
N. V. Makarova ◽  
N. V. Kaverin ◽  
S. Krauss ◽  
D. Senne ◽  
R. G. Webster
Keyword(s):  
North America ◽  
Avian Influenza ◽  
Influenza A ◽  
The Other ◽  
Influenza Surveillance ◽  
Gene Characterization ◽  
Eurasian Lineage ◽  
Antibody Panel ◽  
Antigenic Relationships

Influenza A virus of the H2 subtype caused a serious pandemic in 1957 and may cause similar outbreaks in the future. To assess the evolution and the antigenic relationships of avian influenza H2 viruses, we sequenced the haemagglutinin (HA) genes of H2 isolates from shorebirds, ducks and poultry in North America and derived a phylogenetic tree to establish their interrelationships. This analysis confirmed the divergence of H2 HA into two geographical lineages, American and Eurasian. One group of viruses isolated from shorebirds in North America had HA belonging to the Eurasian lineage, indicating an interregional transmission of the H2 gene. Characterization of HA with a monoclonal antibody panel revealed that the antigenicity of the Delaware strains differed from the other avian strains analysed. The data emphasizes the importance of avian influenza surveillance.

scholarly journals Antigenic Characterization of H3 Subtypes of Avian Influenza A Viruses from North America

2016 ◽  
Vol 60 (1s) ◽  
pp. 346 ◽  
Author(s):  
Elizabeth Bailey ◽  
Li-Ping Long ◽  
Nan Zhao ◽  
Jeffrey S. Hall ◽  
John A. Baroch ◽  
...  
Keyword(s):  
North America ◽  
Avian Influenza ◽  
Influenza A ◽  
Influenza A Viruses ◽  
Antigenic Characterization

Molecular characterization of H1N1 influenza A viruses from human cases in North America

2009 ◽  
Vol 54 (13) ◽  
pp. 2179-2192 ◽  
Author(s):  
Bin Wu ◽  
ChengMin Wang ◽  
GuoYing Dong ◽  
Jing Luo ◽  
BaoHua Zhao ◽  
...  
Keyword(s):  
North America ◽  
Molecular Characterization ◽  
Influenza A ◽  
H1n1 Influenza ◽  
Influenza A Viruses

scholarly journals The impact of seasonal and year-round transmission regimes on the evolution of influenza A virus

2010 ◽  
Vol 278 (1716) ◽  
pp. 2249-2256 ◽  
Author(s):  
Ben Adams ◽  
Alice Carolyn McHardy
Keyword(s):  
Influenza A ◽  
Evolutionary Dynamics ◽  
Vaccine Development ◽  
Herd Immunity ◽  
Wild Type ◽  
Critical Window ◽  
Seasonal Transmission ◽  
Seasonal Epidemics ◽  
Seasonal Circulation ◽  
The Impact

Punctuated antigenic change is believed to be a key element in the evolution of influenza A; clusters of antigenically similar strains predominate worldwide for several years until an antigenically distant mutant emerges and instigates a selective sweep. It is thought that a region of East–Southeast Asia with year-round transmission acts as a source of antigenic diversity for influenza A and seasonal epidemics in temperate regions make little contribution to antigenic evolution. We use a mathematical model to examine how different transmission regimes affect the evolutionary dynamics of influenza over the lifespan of an antigenic cluster. Our model indicates that, in non-seasonal regions, mutants that cause significant outbreaks appear before the peak of the wild-type epidemic. A relatively large proportion of these mutants spread globally. In seasonal regions, mutants that cause significant local outbreaks appear each year before the seasonal peak of the wild-type epidemic, but only a small proportion spread globally. The potential for global spread is strongly influenced by the intensity of non-seasonal circulation and coupling between non-seasonal and seasonal regions. Results are similar if mutations are neutral, or confer a weak to moderate antigenic advantage. However, there is a threshold antigenic advantage, depending on the non-seasonal transmission intensity, beyond which mutants can escape herd immunity in the non-seasonal region and there is a global explosion in diversity. We conclude that non-seasonal transmission regions are fundamental to the generation and maintenance of influenza diversity owing to their epidemiology. More extensive sampling of viral diversity in such regions could facilitate earlier identification of antigenically novel strains and extend the critical window for vaccine development.

scholarly journals ANALYSIS OF POPULATION IMMUNITY AGAINST INFLUENZA PRIOR TO 2014 AND 2015 EPIDEMIC SEASONS

2017 ◽  
pp. 53-60 ◽  
Author(s):  
A. V. Shipovalov ◽  
A. G. Durymanov ◽  
O. V. Petrova ◽  
E. V. Ivanova ◽  
A. V. Epanchintseva ◽  
...  
Keyword(s):  
Human Blood ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Vaccination Campaign ◽  
Herd Immunity ◽  
Influenza Viruses ◽  
The Urals ◽  
Population Immunity ◽  
Clade 2.3.2.1C ◽  
Sera Samples

Aim. Control for the population herd immunity against seasonal influenza viruses as well as for emergence of antibodies against influenza with pandemic potential in human blood sera. Materials and methods. HAI reaction against vaccine and epidemic influenza viruses as well as HPAI viruses A/rook/Chany/32/2015 (H5N1) (clade 2.3.2.1c.) andA/Anhui/01/2013 (H7N9). Results. Among all the sera samples collected in the autumn of 2014 and 2015, none had reacted in HAI against A(H5N1) and A(H7N9) antigens even at 1:10 dilution. Among samples collected in autumn 2014, 41% were positive to A/Califorrna/07/09(HlNlpdm09) virus, 36% - A/Texas/50/2012 (H3N2), 40% - B/Brisbane/60/2008 (Vict.lin.) and 47% reacted in HAI against the B/Massachusetts/2/2012 (Yam.lin.) strain. 22% of all the samples had a titer of at least 40 against all the antigens and only 10% in HAI had a titer of 40 or more against all the vaccine strains. Among the samples collected in autumn 2015, the number of seropositive against A/Califorrna/07/09(HlNlpdm09) varied from 31% in the Urals FD to 46% in the Southern FD. The amount of seropositive against A/Switzerland/9715293/13 (H3N2) strain was at the level of 4 - 13% in all the FDs except Urals, where this parameter was slightly above 30%. The amount of seropositive against vaccine influenza В viruses varied from 23 to 76%. Only 2% of sera had titers in HAI of 40 or above against all the vaccine strains, 29% of all the samples were seronegative. Conclusion. Population immunity in Russia against influenza A(H3N2) is at a very low level, thus socially significant consequences of influenza epidemics in many aspects will depend on the vaccination campaign of autumn 2016.

scholarly journals Characterization of co-circulating swine influenza A viruses in North America and the identification of a novel H1 genetic clade with antigenic significance

2015 ◽  
Vol 201 ◽  
pp. 24-31 ◽  
Author(s):  
Tavis K. Anderson ◽  
Brian A. Campbell ◽  
Martha I. Nelson ◽  
Nicola S. Lewis ◽  
Alicia Janas-Martindale ◽  
...  
Keyword(s):  
North America ◽  
Influenza A ◽  
Swine Influenza ◽  
Influenza A Viruses

scholarly journals Severe cases of seasonal influenza in Russia in 2017-2018

2019 ◽  
pp. 58-64 ◽  
Author(s):  
S. V. Svyatchenko ◽  
A. G. Durymanov ◽  
N. P. Kolosova ◽  
A. S. Gudymo ◽  
N. I. Goncharova ◽  
...  
Keyword(s):  
Influenza A ◽  
Seasonal Influenza ◽  
Effective Means ◽  
Herd Immunity ◽  
Clinical Signs ◽  
Neuraminidase Inhibitor ◽  
Influenza Viruses ◽  
Epidemic Season ◽  
Antibody Titers

Aim.Evaluation of herd immunity prior to the 2017-2018 influenza season, and characterization of influenza viruses isolated from severe or fatal influenza cases and from influenza cases in people vaccinated in the fall of 2017.Materials and methods.Evaluation of herd immunity in hemagglutination inhibition assay. Isolation of influenza viruses. Antigenic and genetic analysis.Results.Prior to epidemic season 33-47% of blood sera samples collected on the territory of Russia showed presence of protective antibody titers against vaccine strains of influenza A, 24-30% of samples — against B/Victoria. During 2017-2018 epidemic season 87 influenza A and B viruses were isolated. A(H1N1)pdm09 strains belonged to clade 6B.1, B/Yamagata strains to clade 3, and B/Victoria strains to clade 1A; they were antigenically similar to corresponding vaccine strains. A(H3N2) viruses belonged to clade 3C.2a and were difficult to characterize antigenically. One strain of influenza virus А(H1N1pdm09) was resistant to oseltamivir and had H275Y amino acid substitution in neuraminidase. All other isolates were susceptible to neuraminidase inhibitors.Conclusion.Influenza vaccination with vaccine effective against current circulating strains and treatment with neuraminidase inhibitor drugs at first manifestation of clinical signs of influenza disease are effective means of population protection against influenza.

The Analyses of Learning Strategies in English as a Second Language: Theoretical Classification and Measurement Test

2020 ◽  
Vol 4 (2) ◽  
pp. 118-129
Author(s):  
Asti Gumartifa ◽  
◽  
Indah Windra Dwie Agustiani
Keyword(s):  
Language Learning ◽  
Learning Outcomes ◽  
Learning Strategies ◽  
Learning Process ◽  
English Learners ◽  
English Language ◽  
Point Of View ◽  
Effective Learning ◽  
The Impact

Gaining English language learning effectively has been discussed all years long. Similarly, Learners have various troubles outcomes in the learning process. Creating a joyful and comfortable situation must be considered by learners. Thus, the implementation of effective learning strategies is certainly necessary for English learners. This descriptive study has two purposes: first, to introduce the classification and characterization of learning strategies such as; memory, cognitive, metacognitive, compensation, social, and affective strategies that are used by learners in the classroom and second, it provides some questionnaires item based on Strategy of Inventory for Language Learning (SILL) version 5.0 that can be used to examine the frequency of students’ learning strategies in the learning process. The summary of this study explains and discusses the researchers’ point of view on the impact of learning outcomes by learning strategies used. Finally, utilizing appropriate learning strategies are certainly beneficial for both teachers and learners to achieve the learning target effectively.

The Algorithm of Characterization of an Action as a Jointly Committed Crime

2018 ◽  
pp. 37-44
Keyword(s):  
Criminal Code ◽  
Point Of View

The article discusses a sequence of activities to identify a crime as jointly committed. The requirements to the algorithm of such activities are formulated. Programme-based and targeted methods applied by the authors allowed detecting a range of stages of the algorithm. The first four stages aim at defining mandatory elements of a crime allowing to characterize it as a jointly committed action. The rest of the stages focus on identifying a type of criminal complicity. In the article, each stage is described. It is emphasized that in each stage there is a special objective. At the same time, all these stages, taken together, constitute a separate module of the program of criminal characterization of an action. From the authors’ point of view, algorithms are necessary not only for detection of crimes and their criminal characterization, but also for answering the question on existence of criminal complicity in each case. Also the authors give their opinions on interpretation of criminal complicity as a legal category. In particular, it is emphasized that not all of crimes merely committed with participation of two or more persons should be understood as jointly committed. It is joint participation that makes a crime jointly committed. Various forms of criminal complicity and types of co-offenders are considered in the article as well. In various crimes, criminal complicity manifests itself differently. Therefore the proposed algorithm can be applied only after identification a specific article of the Russian Criminal Code stipulating the responsibility for the crime committed.

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